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The following study presents a problem found in the internship experience in the course “Inglés Básico II” at Santo Tomás University, located in Santiago. The main objective of this study was to understand the effect of discussion as an active teaching strategy on adult students’ self-perceived competence of L2 in oral activities, according to the students and teacher’s perception. In order to achieve this, different instruments were applied in order to obtain the data needed. These instruments allowed the understanding that discussion has a positive effect on students’ self-perceived competence of L2 in oral activities, mainly in three different categories that emerged from the data collection; self-confidence, social situation, and personality. Furthermore, the students and teacher’s perception towards the effect of this strategy were favorable.

This dissertation examines several aspects of day work from the worker's perspective and the organizations created to mitigate conflict surrounding day labor practices. I use the 2004 National Day Labor Study to compare worker characteristics and labor market outcomes by type of hiring site, investigate factors associated with site preference, and identify obstacles to and challenges of formalizing a day labor hiring site. I draw on qualitative data to investigate the efficacy of worker centers in three areas: labor market outcomes, the mitigation of abuse and hazards, and the civic integration of workers into the communities in which they work and live.The following four research questions guide this study: (1) What are the worker and labor market outcomes of day laborers who frequent informal sites compared to those who frequent worker centers? (2) Are worker centers improving the labor market outcomes of day laborers, mitigating abuses and hazards, and engaging workers civically? (3) What explains a worker's selection of a particular site? (4) Finally, what are some of the obstacles to and challenges of formalizing a day labor site? My findings show that the conditions and outcomes of workers at informal sites differ significantly by key variables compared to day laborers at worker centers. Instances of employer abuse in the form of wage theft, and merchant and police abuse in the form of insults and threats also differ significantly by site type, suggesting better outcomes for day laborers who search for work at worker centers. My findings demonstrate that worker centers help protect workers from wage theft and abuse, and that they also encourage the civic engagement of participants. My analysis on site preference demonstrates that a worker's level of civic engagement and higher age increase the probability of choosing a worker center over an informal site. Channeling workers to worker centers and promoting civic engagement provide an important pathway for those whose immigration status, education, and occupational levels might otherwise predispose them to living in the shadows. Lastly, utilizing a case study approach (including focus group interviews) that observes day laborers in Santa Monica, California, I identify best practices and challenges of formalizing day labor hiring sites. I find that most workers support worker centers but have mixed views on the effectiveness of the job dispatch process and the setting of wage minimums. Respondents identified obstacles in meeting the needs of day laborers including funding, infrastructure and administration, community and worker support, and employer demand for work and workforce development. I conclude by proffering policy solutions and ideas for future research.

Locomotor development is dependent on the maturation of spinal cord circuits controlling motor output, but little is known about the development of the spinal interneurons that control motoneuron activity. This study focused on the development of Renshaw cells (RCs) and Ia inhibitory interneurons (IaINs), which mediate recurrent and reciprocal inhibition, respectively, two basic inhibitory circuits for motorneuron control. Both interneurons originate from the same progenitor pool (p1) giving rise to ventral spinal embryonic interneurons denominated V1. V1-derived interneurons (V1-INs) establish local inhibitory connections with ipsilateral motoneurons and express the transcription factor engrailed-1. This characteristic permitted the generation of transgenic mice that were used in this study to genetically label V1 interneuron lineages from embryo to adult. Adult V1-derived Renshaw cells and IaINs share some similar properties, both being inhibitory and establishing ipsilateral connections; but differ in morphology, location in relation to motor pools, expression of calcium binding proteins (calbindin vs. parvabumin), synaptic connectivity and function. These differences are already present in neonates, therefore the purpose of this study was to determine possible embryonic differentiation mechanisms.Using 5‟-bromodeoxyuridine birth-dating we demonstrated that V1-INs can be divided into early and late born groups. The early group quickly upregulates calbindinivexpression and includes the Renshaw cells, which maintain calbindin expression through life. The second group includes many cells that postnatally upregulate parvalbumin, including IaINs. This later born group is characterized by upregulation of the transcription factor FoxP2 as they start to differentiate and is retained up to the first postnatal week in many V1-derived IaINs. In contrast, Renshaw cells express the transcription factor MafB that seems relatively specific to them within the V1-INs. Furthermore, Renshaw cells appear attracted to the ventral root exit region and follow a unique migratory route to become specifically placed at this location. In contrast, other V1 interneurons settle more medially and far from the ventral root exit region. MafB expression is upregulated in Renshaw cells only after they have reached their final position among motor axons. Therefore, the specific migration of Renshaw cells might be responsible for their final differentiation and unique relationship with motor axons in adult.

Woody plant encroachment, that is, a substantial increase in the abundance of woody plants in a grassland or savanna, occurs in many parts of the world. It often has large effects on plant and animal populations and communities and on ecosystem properties and processes. However, little is known about the dynamics of woody plant encroachment and how these are affected by soils, by topography, and by the spatial pattern of the vegetation. Encroachment in turn can affect the spatial pattern of the vegetation. Using data from historical aerial photographs, I measured changes in woody plant cover and constructed, parameterized and compared a set of dynamic models of woody plant encroachment in central Texas savannas. These models predicted final woody cover from initial woody cover and the initial spatial configuration of woody plants. Then I incorporated soil and topography into these models to determine their effects. Finally, I examined the effects of encroachment on the spatial pattern of the vegetation. Incorporating negative density dependence in our models improved their fit, demonstrating that encroachment is density-dependent. A function that predicted the formation of new woody patches from a density-independent seed supply also improved the models' performance. The improvement in the models that resulted from incorporating the total length of woody-herbaceous edges confirmed that encroachment in this system occurs in part by the outward expansion of woody patches. The spatial pattern of the vegetation changed during woody plant encroachment. Spatial pattern (measured as degree of fragmentation) often had a non-linear relationship with cover. Furthermore, the spatial heterogeneity in fragmentation, that is, plot-to-plot variation in the degree of fragmentation, also changed during encroachment. Topography and soil type had, in general, little effect the dynamics of woody plant encroachment. Therefore, a relatively simple model of woody plant encroachment provided good predictions of woody cover at the end of the time periods. Other systems experiencing woody plant encroachment, forest succession, or invasion by non-native plants could be modeled using the same approach.